2

I'm working on a project that requires me to take values from a CSV file. I've to do further processing with these values and it'd be great if I can have these values in a 2D array. The number of rows and columns of the CSV files changes at regular intervals.

I'm unable to take these values into a 2D array in VB.NET/C#. Can I please have some help on that?

Here the code that I used:

Imports System.IO Public Class Form1 Private Sub ReadCSVFileToArray() Dim strfilename As String Dim num_rows As Long Dim num_cols As Long Dim x As Integer Dim y As Integer Dim strarray(1, 1) As String ' Load the file. strfilename = "test.csv" 'Check if file exist If File.Exists(strfilename) Then Dim tmpstream As StreamReader = File.OpenText(strfilename) Dim strlines() As String Dim strline() As String strlines = tmpstream.ReadToEnd().Split(Environment.NewLine) ' Redimension the array. num_rows = UBound(strlines) strline = strlines(0).Split(",") num_cols = UBound(strline) ReDim strarray(num_rows, num_cols) ' Copy the data into the array. For x = 0 To num_rows strline = strlines(x).Split(",") For y = 0 To num_cols strarray(x, y) = strline(y) Next Next ' Display the data in textbox For x = 0 To num_rows For y = 0 To num_cols TextBox1.Text = TextBox1.Text & strarray(x, y) & "," Next TextBox1.Text = TextBox1.Text & Environment.NewLine Next End If End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click ReadCSVFileToArray() End Sub End Class
Improve this question
1

4 Answers 4

Reset to default
2

You use the CsvReader from here to easily and conveniently read a csv (or other similar data) into a DataTable (or an IDataReader). It is always my first choice for this scenario - fast and pretty robust.

Improve this answer
Sign up to request clarification or add additional context in comments.

2 Comments

Does not appear to be compatible with VS2012. No downvote, just for info.
@Kez in what way? what fails? and what framework are you targeting? (the IDE can target many frameworks - net20, net30, net35, net40, net45, but also netcore ("windows store"), CF, MF, SL, WP7, etc.
1

I'm not disagreeing with Marc Gravell, because you shouldn't try to re-invent the wheel. His solution would perform the best, and there can be many CSV format nuances that can screw up a simple parser such as the one demonstrated below.

With that said, you asked for a CSV parser that returns a 2D array. The code below does just that (jagged array), and should work for a very simple CSV file. This skips a header row in the file.

(sorry it's not in VB, but you can put it in a helper class in your project)

private string[][] GetData(string fileName) { List<string[]> data = new List<string[]>(); using (StreamReader sr = new StreamReader(fileName)) { bool headerRow = true; string line; while ((line = sr.ReadLine()) != null) { if (headerRow) { headerRow = false; } else { string[] split = line.Split(new char[] { ',' }); data.Add(split); } } } return data.ToArray(); }
Improve this answer

Comments

0

Parsing a CSV file can be pretty hard due to all the possible variations of CSV. See: http://en.wikipedia.org/wiki/Comma-separated_values

E.g., think about embedded quotes, commas etc. So it will not be a simple matter of reading lines/strings and splitting them.

Perhaps you are better of by using a third party library

Improve this answer

Comments

0

Since the number of columns and rows change frequently, you could use dynamic lists rather than a fixed 2D array.

List<List<string>> data = new List<List<string>>();

Then as you parse the CSV file you can build up the data dynamically in the above structure, adding a new List<string> to data for each new row in the CSV file.

Update: The VB.NET equivalent is something like

data As New List(Of List(Of String))

That being said, @Mark Gravell's suggestion is a far better solution than doing this yourself.

Improve this answer

Comments

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.